Fosi Audio GR40 Tube DAC Headphone Amp/Preamp (Open Box) [Grade A, Full Warranty]

Product details

• Multifunctional DAC Preamplifier: The GR40 is a versatile tube DAC preamplifier and headphone amplifier in one, it supports Bluetooth/USB/Optical/Coaxial inputs and active speakers/3.5mm headphone output, with a priority mode for headphones.
• High-Resolution Decoding: With the ESS9028Q2M DAC chip, the preamplifier offers superior audio quality and flexibility. The USB sampling rate supports 32Bit/384kHz and DSD256, making an effective noise reduction to ensure lossless audio every time.
• Advanced Bluetooth with Low Latency: Featuring the QCC3031 Bluetooth module, it supports aptX, aptX-HD, and aptX-LL codecs to provide detailed and clean audio sound. Also, you can get a relaxed experience with low latency when watching movies.
• Compact yet Creativity: With its compact form and a combination of preamp volume, bass, and treble controls, the stereo preamplifier produces a sweeter, more organic sound while preserving the midrange and treble frequencies that make music.
• User-Friendly Design: The digital-to-analog audio converter GR40 is designed with user convenience at its core, allowing you to toggle between different audio inputs and restore Bluetooth-a real Plug-and-plug DAC preamplifier without any driver.

Frequently Asked Questions

1. Bluetooth connection by others, what to do?

Long press the Bluetooth reset button for 3 seconds; the Bluetooth indicator will flash, and the GR40 will enter pairing mode. Simply re-pair your device.

2. Using a smartphone as a source in USB mode, why does sound only come from the phone even when connections are correct?

Check if the phone has data transfer enabled. Some models transfer data directly, while others require manual activation of this feature.

3. Can headphones and RCA outputs be used simultaneously?

The GR40 defaults to headphone priority output. To use RCA output, disconnect the headphones.

4. What are suitable tube models for replacement?

Tubes such as EF95, 6Ak5, 6AK5W, 403A/403B, 6J1, 6J1P, 6J2, 6J3, 6J4, 6J5 are compatible. You can test and choose according to your personal preference.

Note: When replacing tubes, ensure the GR40 is turned off and the tubes have cooled down to prevent burns or damage to the product.

Specifications

Input

Bluetooth, USB, Optical, Coaxial

Output

RCA, 3.5mm Headphone Output

Channel

2.0

SNR

≥103dB

Dynamic Range

104dB

Headphone Impedance

32Ω-300Ω

Headphone Outout Power

300mW@16Ω 250mW@32Ω

50mW@250Ω 40mW@300Ω

Frequency Response

20Hz-20kHz(±1dB)

Sampling Rtae

32bit/384kHz; DSD256

Bluetooth Version

5.1

Bluetooth Connection Distance

≥10m

Bluetooth Transmission Format

SBC, AAC, aptX, aptX HD, aptX LL

Voltage Range

DC 12V

Package Contents

• GR40
• 5654W Vacuum Tube*2
• Decorative Ring*2
• Power Adapter
• Bluetooth Antenna
• User Manual